Part of the collegiate trifecta of bros, hos, homework. In this instance, it refers to the preference that many males have for boning with their lady friends (aka hos) instead of doing their work. Also said when describing plans that will result in the act of copulation at the expense of getting an F.

"Hey dude, she called me up again. Yeah, I know I've got a problem set, but her tits were looking pretty juicy the other day. It's definitely a hos before homework situation."